I agree with Curt that the simplest most reliable way to meter snow scenes is in manual putting the snow 1.5 to 2 stops above center- probably closer to 2 for sunlit snow. I would use spot (or the narrowest meter your camera provides) for this.

I have recently purchased my first digital SLR and am currently reading up on techniques and tips for their use. One thing i have seen on a number of occasions is a tip to slightly under expose the shots in order to avoid blown highlights. I shall be travelling to Canada shortly and so have also been reading up on exposure for snowscapes. One of the tips that crops up alot is to slightly over expose since the camera can be 'fooled' by the amount of snow around.

Unfortunately i have not had any snow around me so far to experiment so could anyone suggest a suitable approach since i cannot under and over expose images without resorting to layering mutliple shots in photoshop.. or is that a good approach.

Because the camera meter is calibrated to see the world as 18% gray, then black or white scenes will need a human brain to compensate.

Do this with snow by metering the snow(in manual mode) & open up either the lens or decrease shutter speed by 1 1/2- to 2 stops. Review the camera histogram per the previous posters recommendation. Do the reverse for a black object.Be certain to meter the portion of the scene which is important to you. If the snow by your feet is in shadow but the distant subject is sunlit then you must find sunlit snow to meter. This all goes very quickly after only a bit of practice.

I find I can dispense with a white card for the WhiteBlancing by simple WB on the snow.Enjoy the winter!

Without adjustment you camera will attempt to expose so that snow will come out grey or blue if it comprises much of your picture. To compensate for this you can over expose by 2/3 to 1 2/3 stops. The amount depends on composition and light intensity.

Use your histogram to determine how much over exposure you need. The peak on the right represents the white snow. Generally you want it close to, but not across the right side of the display to make snow look white, but retain some texture.

If your composition varies from scenes with mostly snow to mostly neutral toned subjects with just some snow you will have trouble using Av, Tv or P modes because the required compensation will keep changing. For this reason it is often best to shoot M mode in winter so you have more control.

One process to determine exposure in M mode is to first set exposure on the brightest part of the snow using spot or partial metering so that it is over exposed up to 1 2/3 to 2 stops. Then check exposure on neutral toned subjects to ensure it is reasonable. If not you will have to compromised between blowing out the detail in the snow and under exposing the other subjects. Often it is better to not blow out the detail in the snow and attempt to recover detail in the shadows in processing.

Shoot in raw format. It is easy to make exposure mistakes in snow and it is nice to be able to adjust exposure a bit when converting.